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Forensic investigations in the case of Mr Louvet:
Radioactivity determination in Mr Louvet belongings
To :
Version of :

Pr Mangin (CURML/CHUV)
PD Dr Pascal Froidevaux
Authors : Dr Sébastien Baechler
Pr François Bochud


1. Introduction
The Institute of Radiation Physics (thereafter IRA) received the personal belongings of Mr Louvet by
the University Centre of Legal Medicine (CURML) for investigating a potential radioactivity
contamination with a particular attention to polonium-210 (210Po). Because more than 20 half-lives
have passed between a potential contamination by 210Po and the present measurements, it is necessary
to apply low level techniques to the determination of unsupported


Po (210Po not supported by its

grandmother 210Pb).
Materials and Methods
Surface contamination measurements
Surface contamination measurements were performed using a Berthold LB-122 monitor in / mode
and a Como monitor in

mode. All the set of personal belongings was scanned manually for

radioactive contamination.

Gamma spectrometry measurements
For gamma spectrometry measurements, personal belongings were pooled into 11 samples as shown
in Figure 1. Each sample was then measured on an HPGe gamma spectrometer (measuring time
> 24h). Artificial radionuclides, such as 60Co, 134Cs and 137Cs were investigated, as well as 210Pb.